I recently purchased a 98 TJ Wrangler, I must say so far this is an excellent vehicle. But I was wondering how big of tires I can fit under it stock with no lift, and without having to worry about rubbing on full articulation, and at full turn. I have 235/75r15's right now which equal to about a 28.5" tire I want to go to 31x10.5 but I want to hear from anyone if this will work. Also I only have the 3.07 gears and am wondering if  a 31" tire will suck all the power. Any help would be appreciated.  

I'm not too sure if you can fit 31's on your Jeep with no rubbing.

If you do decide to put on 31x10.50x15 tires, I would go with 4:10 gears.